One theory I have dabbled with about rising inequality in the United States is related to the concept of natural selection. Smart people marry other smart people and have smart children.
One might argue that this pattern has been constant throughout history, and therefore there is no reason to expect it to be any different today.
However, I disagree.
There are four demographic trends that seem to have accelerated this pattern. First, over the past forty years, admission to top universities has become much more meritocratic. In the past, admission to top universities likely depended more on one’s social class than on one’s innate intelligence. Of course, there were certainly exceptions, but I think it is fair to argue that college admissions are far more meritocratic now than they were forty years ago.
Second, the internet boom in the late 1990s drew thousands of high-IQ employees from around the country to places like Silicon Valley, where they established their careers, and married other high-IQ partners. Furthermore, those with more “male-like” brains — that is, brains hard-wired to understand systems rather than empathizing with people — achieved higher status and income than their more-gregarious peers. These so-called “systemizers” include people like Bill Gates and Mark Zuckerberg.
Third, augmenting this technology boom was the influx of highly intelligent immigrants from around the world (which ended after limitations were imposed on immigration policy after 9/11). These people were literally some of the smartest people in their countries and the world, and they came to the United States.
Fourth, the number of women earning math and science degrees accelerated in the 1970s and 80s. These women entered traditionally male professions in unprecedented numbers, where they met their future spouses.
Fast forward to the present day, and many of these people have had offspring. Furthermore, recent decades saw a dramatic increase in autism rates. For instance, according to a recent article in Time, researchers believed that autism was prevalent amongst 1 out of 2,500 children in the 1980s. Today, researchers believe 1 in 110 are on the autism spectrum. Part of this increase is likely due to better screening, and another part is likely because of unknown environmental factors. However, some researchers like Simon Baron-Cohen believe another factor is at play called “associative mating.” In other words, “birds of a feather” tend to “flock together.”
For instance, Baron-Cohen discovered that two to four times as many children in Eindhoven in the Netherlands, home of the Dutch equivalent of Silicon Valley, had autism compared to children in the Dutch cities of Haarlem and Utrecht.
Of course, this theory is still relatively unproven, but it seems compelling. As these parents have children who also tend to be highly intelligent, “systemizers”, a society that favors technological innovation and quantitative skills selects for these children with higher paying jobs and opportunities at a higher rate than it does their peers. Coupled with the tendency for systemizers to be less empathetic than the average person, it is no surprise that many of today’s “wealthy” are not stirred by emotional appeals to help the poor.